Impression roller for duplicators



March Z8, 1939. 'F NIGRA 2,152,561

IMPRESSION ROLLER FOR DUPLICATORS original Filed oct. 22, 1954` INVENToR.

nNn N/GRA ATTORNEY.'

mm3 FERa/N 27 BY Patented Mar. 28, 1939 UNITED STATES PATENT OFFICE IMPRESSION ROLLER FOR DUPLICATORS Ferdinand Nigra, San Francisco, Calif., assigner to Niagara Duplicator Company, San Francisco, Calif., a corporation of California 5 Claims.

The invention relates to an impression roller which is arranged to engage a sheet to be printed against a printing cylinder, and the present application comprises a division of my copending application Ser. No. 749,328, filed October 22, 1934.

An object of the invention is to so mount an impression roller which is freed of any bearing contact between its periods of engagement with successive sheets being printed in a continuously operating duplicator or the like as to permit an axial displacement of the roller Whichmay be urged upon it during its functioning.

Another object is to provide for an automatic return of the roller to its undisplaced position each time it is freed.

A further object is to provide the aforesaid roller mounting means entirely interiorly of the roller.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth or be apparent, in the following description of a typical embodiment thereof, .and in the accompanying drawing in which,

Figure 1 is a fragmentary side elevation of a rotary duplicator mechanism having the impression roller thereof mounted in accordance with the present invention and inoperatively disposed with respect to the printing cylinder of the duplicator.

Figure 2 is an axial section through the impression roller, taken in the plane of the line 2 2 in Figure 1.

Figure 3 is a sectional elevation of the roller and duplicator taken transversely through the roller intermediately thereof, the roller being operatively disposed.

The features of the present invention are incorporated in the fragmentarily shown duplicating machine mechanism I in which a stencil 2 is carried on a rotary cylinder 3 for printing engagement with a sheet of paper or other material for receiving printing. The printing cylinder 3 is suitably supported for rotation about an horizontal axis and may be actuated by hand or by a suitable motor.

By reference to Figure 1, it will be noted that a sheet of print-receiving material which has been moved from the top of a stack of sheets on a feed table I5 to dispose its front end portion between pairs of upper and lower feed rollers I6 and I'l, is thereafter engaged by and between said rollers and is thereby advanced forwardly for the disposal of its front end portion between the stencil 2 on the rotary cylinder 3 and an impression roller I8, as in Figure 3, and is finally gripped between the cylinder and impression roller to continue the feeding movement of the sheet while the latter is being pro- 5 gressively printed.

The impression roller I8 is mounted for its free rotation on a shaft I9 which is carried by and between corresponding and rearward ends of y, lever-like members 20 which are intermediately 'l0 pivoted on a xedly disposed rock-shaft 2|, said shaft being disposed toward the front or feeding end of the machine with respect to the roller I8.

The forward ends of the lever members 20 are y connected by a bar 22, and a tension spring 23 l5 extends generally rearwardly from the bar 22 to constantly urge a resilient engagement of the impression roller I8 against the cylinder 3. 'I'he extremities of the shaft I9 and the bar 22 pivotally engage the ends of the levers 2|] whereby the 2'0 generally planar assembly of these members may be distorted transversely thereof if such is required to insure an even bearing of the impression roller with and along the cylinder.

Arms 24 extend rigidly and radially from the T25 shaft 2l for simultaneous engagement with the bar 22 as a means to rock the levers 20 to dispose the roller I8 out of engagement with the cylinder. An arm 25 extends rigidly from the shaft 2I in angular relation to the arm 24 thereat, 30 and a tension spring 26 is operative against the free end of the arm 24 whereby the arm 25 is resiliently urged to maintain an engagement thereof with an adjustable stop 21; it will be understood that the stop 21 may determine one 35 limit of oscillation of the shaft 2|. The rocking of the shaft 2| to displace the roller I 8 at the appropriate time in the feeding cycle of a sheet I4 may be effected in any suitable manner; mechanism for providing the complete cycle by '40 and in synchronism with the rotation of the cylinder is shown and described in detail in my copending application Ser. No, 749,328 previously referred to.

The shaft I9 which carries the roller I8 is 45 stepped adjacent its extremities to provide reduced end portions 3l and 38 terminatingat annular shoulders 39 and engaged in aligned eyes provided in corresponding extremities of the arms 20 which carry the roller to and from its de- 50 scribed operative position. An helical spring 40 encircles the shaft portion 38 and is compressed between the shaft shoulder 39 and the adjacent arm 20, it being noted that the shaft portion 38 is long enough to permit a longitudinal shifting of u -provided to prevent the latter.

the shaft to disengage its other end from the other arm 20; in this manner, the roller I8 may be readily removed or replaced.

The roller I8 comprises a core tube 4I carrying a relatively thick and resilient tread 42 for engaging beneath a sheet I4 at the stencil on the cylinder.-A -Suitable anti-friction bearing assemblies are mounted in the core tube 4I at opposite ends thereof, said bearings having their outer ball races 44 snugly fitting the bore of the tube 4I and their tubular inner ball races 45 slidably receiving intermediate shaft portions 46 and 4'I which extend from the shoulders 39 and 40 respectively. The bearing races 44 may be retained in the tube 4I by turning end portions of the tube inwardly to provide retaining lugs. VThe present arrangement for enclosing the bearings within the roller is understood to minimize the probability of ink and/or clust getting therein.

Inwardly of the different bearing races 45 and in spaced relation thereto, the shaft I9 is provided with radial shoulders 49; as shown, the shoulders 49 are defined at the ends of an enlarged central shaft portion I. Helical compression springs 52 encircle the shaft portions 46 and 41, and are respectively operative between the shoulders 49 and the inner bearing races v45; it will be obvious that the springs 52 are c'oactive to yieldingly retain the roller in a longitudinally centered position on the shaft.

Recalling theI fact that in sheet handling devices where a sheet of material is gripped and advanced between coacting rollers, a very slight variation from. a true cylinder of uniform crosssection of one or both rollers, or a lack of true parallelism of the roller axes, or a variation in sheet thickness, will operate to` urge a lateral motion of a sheet gripped thereat whereby the sheet may be wrinkled or even torn, means are In the present duplicator, the printing cylinder 3 is supported against any longitudinal Vshifting thereof, and the .disclosed mounting of the impression roller I8 for a possible axial shifting thereof against the slight resistance of a spring 52 is designed to eliminate any lateral stresses which the roller and cylinder might develope in the sheet as it is advanced between them; this feature has been found particularly valuable when applied to duplicating machines of the present type. It will be understood that the roller I8 is automati-l cally recentered each time it is lowered to an inoperative position, the latter occurring after each sheet is printed and discharged.

From the foregoing description taken in connection with the accompanying drawing, the advantages of the construction and use of the device will be readily understood by those skilled in the art to which the invention appertains. While I have described the features and the principle of operation` of a structure which I now consider to be a preferred embodiment of my invention, I desire to have it understood that the showing is primarily illustrative, and that such changes may be made, when desired, as fall within the scope of the following claims.

I claim:

1. In a rotary duplicator, a printing cylinder mounted against axial shifting thereof, a hollow impression roller for coaction with said cylinder, a shaft engaged through said roller, anti-friction bearings mounting the roller on the shaft for rotation thereabout, a frame carrying said shaft for movements of the roller to and from an oper- 'ative relation thereof to the cylinder during each rotative cycle of the cylinder, and spring means disposed within the roller and coactive between the roller and shaft longitudinally thereof for yieldingly urging a retention of the roller in a centered positionthereof on the shaft.

2. Ina rotary duplicator or the like, a printing cylinder mounted "against axial shifting thereof, a tubular impression roller for coaction with said cylinder to dispose ,a sheet of print-receiving material thereagainst for its printing, a shaft engaged through said roller, mutually spaced antifriction bearings within the roller and mounting the roller on the shaft for rotation thereabout, a frame carrying said shaft formovements of the roller to and from an operative relation thereof during each operative cycle of the cylinder, and spring means disposed between the bearings and coactive between the roller and shaft longitudinallyV thereof for yieldingly urging a retention of the roller in a normal position thereof on the shaft.

3. In a rotary duplicator or the like, an impressionroller, a printing cylinder with which said roller is coactive during only a portion of each operative cycle of the cylinder, a shaft means rotatably mounting said roller, and spring means coactive between the roller and sha-ft means axially thereof for urging a retention of the roller in a normal position thereof with re'- spect to the shaftmeans while permitting any longitudinal displacement of the roller which may be urged upon it during and by reason of the coaction of the cylinder and rolle-r.

. 4. In a rotary printing machine, a printing cylinder mounted against axial shifting thereof, an impression roller for coaction with said cylinder laterally thereof and longitudinally therealong, means mounting said roller for its lateral movement to and from an operative relation thereof to the cylinder during each rotative cycle of the cylinder andl for its independent axial shifting between limiting positions in its axial line, and spring means constantly operative axially of the roller for yieldingly urging a retention of the roller` in a centered position thereof which is intermediate of said limiting positions therefor.

5. In a printing machine, a rotary printing cylinder mounted against. axial shifting thereof, an impression roller for coaction-with said cylinder, a frame carrying said roller for its lateral movement to andfrom an operative relation to the cylinder during each printing cycle thereof and for its longitudinal slfnfting in the frame, and spring means constantly operative for yieldingly urging a retention of the roller in an axiallyY centered position Vwith yrespect to its permitted longitudinal movement. v

FERDINAND NIGRA. 

